There are free tools that will detail the brand and model of each component in your PC. I use HWiNFO64, you can get it here.
https://www.hwinfo.com/download/
Your PSU has enough wattage for your spec, but that alone means little, it needs to be a decent quality one.
Another cause of video problems is sometimes just a bad quality video cable that connects the graphics card to the display, and it's something that can be checked fairly inexpensively. Sometimes wiggling the ends of the cable will reveal if it's faulty by what you see on screen when you do.
Regarding the HDD the game is installed on, what size is it and how much free space does Windows say it has? Use the Windows calculator and multiply .15 times the drives actual space. That's how much free space it should have at all times.
On defrag tools, I've tried many, but my favorite is Raxco's PerfectDisk. It's Microsoft certified and has a stealth mode where it runs in the background, but only when no resource intense programs are running. With ANY defrag tool though, you want to set it to ignore solid state drives (SSD, NVMe), as these drives don't require defragging, and do their own version of it called TRIM. Defragging them will just make them wear faster.
Did you by chance check for software conflicts as I suggested, like background apps or startups running? Quite often these mysteries end up being solved by the user eventually reporting back that a certain program they were using was causing the problem.